What happens if you hover the mouse to the top?

• https://support.mozilla.org/kb/how-to-use-full-screen

Does it has effect if you toggle the browser.fullscreen.autohide to false on the about:config page?

You can open the about:config page via the location/address bar. You can accept the warning and click "I'll be careful" to continue.

• http://kb.mozillazine.org/about:config

When I hover my mouse at the top I get the title f the tab but not my address bar or tab bar.

It does nothing when I toggle browser.fullscreen.autohide

Try to rename (or delete) the xulstore.json file in the Firefox profile folder.

You can use this button to go to the currently used Firefox profile folder:

• Help > Troubleshooting Information > Profile Directory: Show Folder (Linux: Open Directory; Mac: Show in Finder)
• http://kb.mozillazine.org/Profile_folder_-_Firefox

I deleted it and nothing happened. I restarted FF too.

Try to remove the Firefox plist file (org.mozilla.firefox.plist).

• http://www.macfixit.com/article.php?story=20060606082246983 How .plist files become corrupt and troubleshooting the results

Go to "~/Library/Preferences" and remove the plist file for Firefox (org.mozilla.firefox.plist)

It won't let me fully delete that file.

Sorry for the trouble!

I figured it out!! I had to install classic theme restorer, and delete tabs on bottom and have bookmark toolbar selected. :) Thank you for your help!